This invention relates to a file management method for use in a computer system including a storage apparatus, a metadata server for managing metadata of files stored in the storage apparatus, a business server for executing predetermined business processing, and an analysis server for executing analytical processing on data used by the business server.
In a computer system in which a plurality of computers and a plurality of file servers corresponding to storage apparatus are coupled via a network, business programs operating on the computers execute business logic. The business programs include, for example, programs that autonomously operate, such as a document management system, and interactive programs such as a word processing program used by a user.
Business data required by the business program to execute the logic may be stored in the file server to flexibly perform a configuration change of a system and management of a storage capacity.
Moreover, it is a common practice that an analysis program operating on a computer different from the business program executes the analytical processing such as statistical processing on the business data stored in the file server to obtain information useful for business management.
The business program may remove a file stored in the file server in the course of the logic. On the other hand, it is preferred that the analysis program obtain and analyze all files in the computer system tracing back in time, including the file removed from the file server, in order to obtain more useful information.
As a method for allowing the removed file to be read later, there is known a method using a backup system. The backup system periodically reads data stored in the file server and copies the data in another storage apparatus for backup. However, the backup system holds the same data in the file server and the storage apparatus for backup, and hence a use efficiency of storage spaces is low.
Moreover, as another method, there is known a method using a snapshot function of the file server. The snapshot function is used so that a plurality of states of the file server at a time point in the past may be held while suppressing an amount of consumption of the storage spaces. However, there is a limit in the number of snapshots that can be created, and hence, for example, the method is not suited for an application where a file that was present at a time point tracing back in time 5 years or more is to be obtained.
Moreover, as a method of moving a file to another storage apparatus, there is known an archive system. The archive system is a system for moving a file that satisfies a predetermined condition (for example, file that has not been modified for a certain period of time) to another storage. However, the archive system deals only with files that are present in the file system, and cannot specify “removed files” as a condition, for example.
Moreover, in Japanese Patent Application Laid-open No. 2008-17049, there is disclosed a technology in which a file removed by a user's operation is not actually removed but is saved in another storage space so that the file can be restored later.